1. Hypothyroidism is a clinical syndrome where the thyroid gland fails to produce sufficient thyroid hormones. 2. It can be primary, meaning it is caused by problems with the thyroid gland itself, or central/secondary, caused by problems with the pituitary gland or hypothalamus. 3. Symptoms affect many body systems and include fatigue, weight gain, dry skin, constipation, muscle weakness, decreased heart rate, impaired cognition and more.

1. ‫الرحیم‬ ‫الرحمن‬ ‫هللا‬ ‫بسم‬
BY DR.LAILMAAH HABIBI 3RD year of KABUL RBH (AFG)
2017
1

2. 2

3. Objectives
1. Definition
2. Classification
3. Clinical manifestation
4. Lab evaluation
5. Complication
6. Medication
3

4. Hypothyroidism is a clinical syndrome n which the thyroid gland
fails to produce or to secrete sufficient circulating thyroid hormone to meet
the needs of the peripheral tissues.
Copyright © 2011 Abbott India Limited. All rights reserved

5.  Causes of hypothyroidism
5

6. Primary hypothyroidism
 Primary hypothyroidism(90%)
 (TSH)
 free (T4)
 Congenital
 Aquired
o Hashimotos thyroiditis
o I deficiency
o Goitrogens
o Cytokines
o Thyroid infiltration
o drugs
o Iatrogenic
6

7. Central Hypothyroidism or 2ndry
 Secondary (central) hypothyroidism
1. serum T4
2. serum TSH
 Acquired
o Pituitary &hypothalamic disorders
o Dopamine & or severe stress
 Congenital
o TSH deficiency/structural abnormality
o TSH receptor defect
o TRH deficiency
7

8. Other types
 Transient H
 Silent thyroiditis (postpartum & Subacute)
 Withdrawal of thyroxine Rx
 After Rx or surgery for Graves' disease
 Consumptive H
 hemangiomas ,hemangioendotheliomas
 Resistance to Thyroid Hormone
 generalised or pituitary dominant
8

9. Other types con..
 Subclinical hypothyroidism
 Asymptomatic patient
 TSH
 Normal FT4 & FT3
9

10.  Clinical (overt) H
o Symptomatic patient
o Elevated TSH level
o low levels of FT4 and FT3
Euthyroid sick syndrome
o Pts without known thyroid disease
o FT4
o TSH not elevated.
 severe illness, caloric deprivation, or major surgery.
 Serum TSH tends to be suppressed in severe nonthyroidal illness
10

11. Myxedema crisis
• A life-threatening state with
• Impaired cognition {confusion to somnolence to coma
(myxedema)}
• Elderly women (stroke or stopped taking thyroxine)
• Convulsions & CNS signs
11

12. Precipitating events
1. Infection, sepsis
(pneumonia)
2. Cold exp
3. CVA
4. Drug effect
5. MI
6. GI bleeding
7. Trauma
8. burns
9. CHF
10. Hypoxia
11. Na
12. Capnea
13. Glycemia
14. Ca
15. DKA
12

13. SIGNS AND SYMPTOMS OF HYPOTHYROIDISM (DESCENDING
ORDER OF FREQUENCY)
13

14. Effect of Hypothyroidism on Organs
Cardiovascular
• VC
• HR
• DBP
Central Nervous
• Concentration
• Lack of interest
• Depression
14

15. Effect of Hypothyroidism on Organs
 GIS
o GI motility
o Constipation
 Hepatic
o LDL / TC
o LDL + triglycerides
 Renal
o Fluid retention
o GFR
15

16. 16
Effect of Hypothyroidism on Organs
Musculoskeletal
 Muscle stiffness, cramps, pain,
weakness, myalgia
 Slow muscle-stretch reflexes,
muscle enlargement, atrophy

17. Reproductive
o Arrest of pubertal development
o Reduced growth velocity
o Menorrhagia, Amenorrhea
o Anovulation, Infertility
17
Effect of Hypothyroidism on Organs

18. 18
Effect of Hypothyroidism on Organs
Skin and Hair
Thickening and dryness of skin
Dry, coarse hair, Alopecia
Loss of scalp hair and / or lateral
eyebrow hair

19. Associated conditions
 Type 1 DM
 Addison's disease
 Pernicious anemia
 Vitiligo
 Alopecia areata
 Celiac disease
 Dermatitis Herpatiformis
 Chronic Active Hepatitis
 RA, SLE, Sjogren syndrome
 Thyroid associated ophthalmopathy( in 5%)
 Turner syndrome, Down’s syndrome
19

20. 20

21. Drug Clearance
 Clearance of many drugs are decrease :
o Antiepileptic
o Anticoagulant
o Anesthetic
o Hypnotic & Opioid
21

22. Hashimoto's encephalopathy
 A steroid-responsive syndrome associated with:
o TPO antibodies
o myoclonus & slow-wave activity on EEG
o An immunemediated rather than effect of an altered
thyroid state on the CNS
22

23. 23
FREETHYROXINEorFT4
EUTHYROID
LOW NORMAL HIGH
THYROID STIMULATING HORMONE - TSH
TFT: Best screening test for hypothyroidism is the serum TSH
How to interpret results ?
Nine Square Game To evaluate our Thyroid patient
Lab Exam

24. 24
FREETHYROXINEorFT4
PRIMARY
HYPOTHYROID
LOW NORMAL HIGH
THYROID STIMULATING HORMONE - TSH
BASIC THYROID EVALUATION

25. 25
FREETHYROXINEorFT4
SECONDARY
HYPOTHYROID
LOW NORMAL HIGH
THYROID STIMULATING HORMONE - TSH
BASIC THYROID EVALUATION

26. 26
FREETHYROXINEorFT4
SUB-CLINICAL
HYPOTHYROID
LOW NORMAL HIGH
THYROID STIMULATING HORMONE - TSH
BASIC THYROID EVALUATION

27.  Hyponatremia, Hypoglycemia & Anemia
 levels of LDL,TG, LP, liver enzymes, CK &
Prolactin
 Semen analysis
 FNA biopsy
 Ab against TPO and TG are high
27
Other Abnormalities:

28. The Dx of Myxedema Coma
 Abn TSH & FT4 + nonpitting edema
 Hypoventilation , Hypothermia & Stupor
 Hyponatremia , Hypoglycemia , Hypotension and Infection
are confirmatory

29. Complications
 CAD & HF
 Bacterial pneumonia , Megacolon
 Adrenal crisis
 Infertility
 Miscarriage
 Myxedema crisis
29

30.  Goal is to normalize TSH (lower half of the reference
range)
 Levothyroxine (HL 7 days) on empty stomach
 Levothyroxine dosage according to:
o Clinical response
o TSH
 Keep TSH (0.4 and 2.0 milli- units/L)
30
Treatment

31.  Clinical assessment for adrenal insufficiency and
angina
 Levothyroxine doses
o Healthy young and middle aged adults 25–75 mcg/d
o Lower doses for very mild hypothyroidism
o Treat pregnant women with higher doses of 100–150
mcg/d
31
Treatment con..

32. Determinants of Thyroxine Requirements
 Age
 Severity and duration
 Weight
 Malabsorption
 Pregnancy
 Presence of CVD
 Concomitant drug therapy
32

33.  Smaller doses (25–50 mcg /d):
o CAD
o 60 y
 Higher initial doses:
o severely hypothyroid
 The dose can be increased by 25 mcg every 1–3 weeks
until the pts is euthyroid
33

34.  Larger initial IV doses of levothyroxine
o 400 mcg as a loading dose
o followed by 50–100 mcg IV/d
 IV liothyronine (T3, Triostat) 5–10 mcg /8 h /48 h
 Blankets warming for hypothermia
 Intubation & MV for hypercapnia
 Infections
 hydrocortisone
34
Myxedema Crisis Rx

35. During pregnancy
 1st trimester
 TSH drops
 FT4 rise
 FT4 is helpful in
evaluation
 Check TSH /4wk
35

36. 36